1 files changed, 77 insertions, 15 deletions

diff --git a/fs/ext4/xattr.c b/fs/ext4/xattr.c
index e88748e55c0f..e56c9ed7d6e3 100644
--- a/fs/ext4/xattr.c
+++ b/fs/ext4/xattr.c
@@ -122,6 +122,58 @@ const struct xattr_handler *ext4_xattr_handlers[] = {
         NULL
 };
 
+static __le32 ext4_xattr_block_csum(struct inode *inode,
+                                    sector_t block_nr,
+                                    struct ext4_xattr_header *hdr)
+{
+        struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
+        struct ext4_inode_info *ei = EXT4_I(inode);
+        __u32 csum, old;
+
+        old = hdr->h_checksum;
+        hdr->h_checksum = 0;
+        if (le32_to_cpu(hdr->h_refcount) != 1) {
+                block_nr = cpu_to_le64(block_nr);
+                csum = ext4_chksum(sbi, sbi->s_csum_seed, (__u8 *)&block_nr,
+                                   sizeof(block_nr));
+        } else
+                csum = ei->i_csum_seed;
+        csum = ext4_chksum(sbi, csum, (__u8 *)hdr,
+                           EXT4_BLOCK_SIZE(inode->i_sb));
+        hdr->h_checksum = old;
+        return cpu_to_le32(csum);
+}
+
+static int ext4_xattr_block_csum_verify(struct inode *inode,
+                                        sector_t block_nr,
+                                        struct ext4_xattr_header *hdr)
+{
+        if (EXT4_HAS_RO_COMPAT_FEATURE(inode->i_sb,
+                EXT4_FEATURE_RO_COMPAT_METADATA_CSUM) &&
+            (hdr->h_checksum != ext4_xattr_block_csum(inode, block_nr, hdr)))
+                return 0;
+        return 1;
+}
+
+static void ext4_xattr_block_csum_set(struct inode *inode,
+                                      sector_t block_nr,
+                                      struct ext4_xattr_header *hdr)
+{
+        if (!EXT4_HAS_RO_COMPAT_FEATURE(inode->i_sb,
+                EXT4_FEATURE_RO_COMPAT_METADATA_CSUM))
+                return;
+
+        hdr->h_checksum = ext4_xattr_block_csum(inode, block_nr, hdr);
+}
+
+static inline int ext4_handle_dirty_xattr_block(handle_t *handle,
+                                                struct inode *inode,
+                                                struct buffer_head *bh)
+{
+        ext4_xattr_block_csum_set(inode, bh->b_blocknr, BHDR(bh));
+        return ext4_handle_dirty_metadata(handle, inode, bh);
+}
+
 static inline const struct xattr_handler *
 ext4_xattr_handler(int name_index)
 {
@@ -156,12 +208,22 @@ ext4_xattr_check_names(struct ext4_xattr_entry *entry, void *end)
 }
 
 static inline int
-ext4_xattr_check_block(struct buffer_head *bh)
+ext4_xattr_check_block(struct inode *inode, struct buffer_head *bh)
 {
+        int error;
+
+        if (buffer_verified(bh))
+                return 0;
+
         if (BHDR(bh)->h_magic != cpu_to_le32(EXT4_XATTR_MAGIC) ||
             BHDR(bh)->h_blocks != cpu_to_le32(1))
                 return -EIO;
-        return ext4_xattr_check_names(BFIRST(bh), bh->b_data + bh->b_size);
+        if (!ext4_xattr_block_csum_verify(inode, bh->b_blocknr, BHDR(bh)))
+                return -EIO;
+        error = ext4_xattr_check_names(BFIRST(bh), bh->b_data + bh->b_size);
+        if (!error)
+                set_buffer_verified(bh);
+        return error;
 }
 
 static inline int
@@ -224,7 +286,7 @@ ext4_xattr_block_get(struct inode *inode, int name_index, const char *name,
                 goto cleanup;
         ea_bdebug(bh, "b_count=%d, refcount=%d",
                 atomic_read(&(bh->b_count)), le32_to_cpu(BHDR(bh)->h_refcount));
-        if (ext4_xattr_check_block(bh)) {
+        if (ext4_xattr_check_block(inode, bh)) {
 bad_block:
                 EXT4_ERROR_INODE(inode, "bad block %llu",
                                  EXT4_I(inode)->i_file_acl);
@@ -369,7 +431,7 @@ ext4_xattr_block_list(struct dentry *dentry, char *buffer, size_t buffer_size)
                 goto cleanup;
         ea_bdebug(bh, "b_count=%d, refcount=%d",
                 atomic_read(&(bh->b_count)), le32_to_cpu(BHDR(bh)->h_refcount));
-        if (ext4_xattr_check_block(bh)) {
+        if (ext4_xattr_check_block(inode, bh)) {
                 EXT4_ERROR_INODE(inode, "bad block %llu",
                                  EXT4_I(inode)->i_file_acl);
                 error = -EIO;
@@ -492,7 +554,7 @@ ext4_xattr_release_block(handle_t *handle, struct inode *inode,
                 if (ce)
                         mb_cache_entry_release(ce);
                 unlock_buffer(bh);
-                error = ext4_handle_dirty_metadata(handle, inode, bh);
+                error = ext4_handle_dirty_xattr_block(handle, inode, bh);
                 if (IS_SYNC(inode))
                         ext4_handle_sync(handle);
                 dquot_free_block(inode, 1);
@@ -662,7 +724,7 @@ ext4_xattr_block_find(struct inode *inode, struct ext4_xattr_info *i,
                 ea_bdebug(bs->bh, "b_count=%d, refcount=%d",
                         atomic_read(&(bs->bh->b_count)),
                         le32_to_cpu(BHDR(bs->bh)->h_refcount));
-                if (ext4_xattr_check_block(bs->bh)) {
+                if (ext4_xattr_check_block(inode, bs->bh)) {
                         EXT4_ERROR_INODE(inode, "bad block %llu",
                                          EXT4_I(inode)->i_file_acl);
                         error = -EIO;
@@ -725,9 +787,9 @@ ext4_xattr_block_set(handle_t *handle, struct inode *inode,
                         if (error == -EIO)
                                 goto bad_block;
                         if (!error)
-                                error = ext4_handle_dirty_metadata(handle,
-                                                                   inode,
-                                                                   bs->bh);
+                                error = ext4_handle_dirty_xattr_block(handle,
+                                                                      inode,
+                                                                      bs->bh);
                         if (error)
                                 goto cleanup;
                         goto inserted;
@@ -796,9 +858,9 @@ inserted:
                                 ea_bdebug(new_bh, "reusing; refcount now=%d",
                                         le32_to_cpu(BHDR(new_bh)->h_refcount));
                                 unlock_buffer(new_bh);
-                                error = ext4_handle_dirty_metadata(handle,
-                                                                   inode,
-                                                                   new_bh);
+                                error = ext4_handle_dirty_xattr_block(handle,
+                                                                      inode,
+                                                                      new_bh);
                                 if (error)
                                         goto cleanup_dquot;
                         }
@@ -855,8 +917,8 @@ getblk_failed:
                         set_buffer_uptodate(new_bh);
                         unlock_buffer(new_bh);
                         ext4_xattr_cache_insert(new_bh);
-                        error = ext4_handle_dirty_metadata(handle,
-                                                           inode, new_bh);
+                        error = ext4_handle_dirty_xattr_block(handle,
+                                                              inode, new_bh);
                         if (error)
                                 goto cleanup;
                 }
@@ -1193,7 +1255,7 @@ retry:
                 error = -EIO;
                 if (!bh)
                         goto cleanup;
-                if (ext4_xattr_check_block(bh)) {
+                if (ext4_xattr_check_block(inode, bh)) {
                         EXT4_ERROR_INODE(inode, "bad block %llu",
                                          EXT4_I(inode)->i_file_acl);
                         error = -EIO;